A brief how-to for common snowpack tests to locate and assess instabilities within the snowpack, presented by Mike Conlan.  Start times of tests in this video are as follows:

  1:32  Compression Test
  5:06  Deep Tap Test
  7:28  Extended Column Test
10:54  Rutschblock Test
14:48  Propagation Saw Test
18:48  Shovel Shear Test
20:49  Hand Shear Test
22:11  Concluding remarks on initiation, propagation, and limitations.

Fracture character video:  http://vimeo.com/30996756

Common snowpack tests

This video explains how to conduct numerous snowpack tests the section on compression tests begins at 1:32. The video is by Mike Conlan, a forecaster for Avalanche Canada.

A compression test is a snowpack test that allows someone to test the strength of weak layers in the upper snowpack. It involves applying an incremental load to a narrow column of snow and then monitoring it for its tendency to fracture, as well as for the character of any fracture that occurs. A sudden result indicates greater instability than a resistant result. 

Photo: Conducting a compression test. By Mark Grist